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排序方式: 共有66条查询结果,搜索用时 31 毫秒
41.
Isolation of two populations of sperm cells and microelectrophoresis of pairs of sperm cells from pollen tubes of tobacco (Nicotiana tabacum) 总被引:1,自引:1,他引:0
Prior research has indicated that the two sperm cells of Nicotiana tabacum are dimorphic, suggesting that they may participate in preferential fertilization during in vivo fusion with the egg and
central cells. To probe the mechanism of potential preferential fertilization in this plant, it will be necessary to use modern
sensitive molecular techniques. For this purpose, two individual populations of two sperm cells, constituting the Svn (associated
with the vegetative nucleus) and Sua (unassociated with the vegetative nucleus), were isolated in the thousands from tobacco
pollen tubes with a micromanipulator as a preliminary step toward research on gametic recognition using molecular techniques.
Microelectrophoresis of paired sperm cells from a single pollen tube was conducted at different developmental stages. Sperm
cells isolated from 1-, 2-, 3- and 4-cm stylar lengths migrated to the negative pole, with the Sua displaying significantly
greater electrophoretic mobility than the Svn, reflecting a more positively charged cell surface on the Sua. The sperm cells
isolated from 1-cm style are very sensitive to electron potential in an electrophoretic field, presumably reflecting that
they are still in a young state. Differences in cell surface charge between the Sua and Svn may be related with cell fate
during fertilization.
Supported by National Natural Science Foundation of CHINA (30170060) 相似文献
42.
Role of ChREBP in hepatic steatosis and insulin resistance 总被引:1,自引:0,他引:1
43.
Gorelova NB Korenberg EI Postic D Iunicheva IuV Riabova TE 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2001,(4):10-12
18 Borrelia isolates obtained from adult ticks of the Ixodes ricinus species, collected from different plants in April 2000 in the Khostinsk region of the Krasnodar Territory in the vicinity of the health resort of Matsesta not far from Sochi, were identified by means of PCR and the analysis of polymorphism of the restriction fragments of ribosomal rrf-rrl spacer amplicon. Among them, in addition to Borrelia species, found in Russia earlier (B. garinii, B. afzelii, B. valaisiana and B. lusitaniae), the classical causative agent of Lyme borreliosis (B. burgdorferi sensu stricto) was detected for the first time. The isolated strain (lr-4721) is now kept in the collection of the Borreliosis Center of the Ministry of Health of Russia (the Laboratory of Infections Vectors at the Gamaleya Research Institute of Epidemiology and Microbiology). The probable role of this infective agent in infectious pathology in Russia is discussed. 相似文献
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Tissue-specific knockout of the insulin receptor in pancreatic beta cells creates an insulin secretory defect similar to that in type 2 diabetes 总被引:67,自引:0,他引:67
Dysfunction of the pancreatic beta cell is an important defect in the pathogenesis of type 2 diabetes, although its exact relationship to the insulin resistance is unclear. To determine whether insulin signaling has a functional role in the beta cell we have used the Cre-loxP system to specifically inactivate the insulin receptor gene in the beta cells. The resultant mice exhibit a selective loss of insulin secretion in response to glucose and a progressive impairment of glucose tolerance. These data indicate an important functional role for the insulin receptor in glucose sensing by the pancreatic beta cell and suggest that defects in insulin signaling at the level of the beta cell may contribute to the observed alterations in insulin secretion in type 2 diabetes. 相似文献
47.
Effect of Administered Interferon on Rabies in Rabbits 总被引:2,自引:0,他引:2
This study describes the effect of interferon on the survival of rabbits infected with a street strain of rabies virus. Interferon was prepared by collecting serum from rabbits injected with Newcastle disease virus and was characterized by biological and physicochemical methods. Rabbit serum interferon mixed and incubated with a suspension of rabies virus did not neutralize its infectivity. Rabbits were inoculated into the hind leg muscle with approximately 80 LD(50) of virus. Interferon was administered intravenously or intramuscularly, or by both methods, in the same or opposite leg as virus. Mortality due to rabies was significantly reduced by the concurrent administration of 8 x 10(5) units of interferon divided between the site of virus inoculation and intravenously. There was less protection if 3 hr elapsed between the inoculation of virus and interferon. Treatment given 24 hr after infection did not prevent death but prolonged the incubation period. 相似文献
48.
Delineation of Borrelia burgdorferi sensu stricto, Borrelia garinii sp. nov., and group VS461 associated with Lyme borreliosis. 总被引:66,自引:0,他引:66
G Baranton D Postic I Saint Girons P Boerlin J C Piffaretti M Assous P A Grimont 《International journal of systematic bacteriology》1992,42(3):378-383
We studied 48 Borrelia isolates that were associated with Lyme borreliosis or were isolated from ticks and identified three DNA relatedness groups by using the S1 nuclease method. The three DNA groups (genospecies) were associated with specific rRNA gene restriction patterns, protein electrophoresis patterns, and patterns of reactivity with murine monoclonal antibodies. Genospecies I corresponded to Borrelia burgdorferi sensu stricto since it contained the type strain of this species (strain ATCC 35210); this genospecies included 28 isolates from Europe and the United States. Genospecies II was named Borrelia garinii sp. nov. and included 13 isolates from Europe and Japan. Genospecies III (group VS461) included seven isolates from Europe and Japan. 相似文献
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Baruch MC Warburton DE Bredin SS Cote A Gerdt DW Adkins CM 《Nonlinear biomedical physics》2011,5(1):1-15